Constant rate let-offs



July 7,1959

T. J. OLIVER CONSTANT RATE LET-OFFS Filed Jan. 10, 1957 m i 3 0; I "0 ik I 3? f w l Tomcw J 02127423 United States Patent 2,893,441 PatentedJuly 7,. 1959 CONSTANT RATE LET-OFFS Thomas J. Oliver, Wetumpka, Ala.,assignor to H. F. Livermore Corporation, Boston, Mass., a corporation ofDelaware Application January 10, 1957, Serial No. 633,477

6 Claims. (Cl. 139-108) This invention relates in general to let-ofisfor looms, and in particular to let-offs of the well-known Roper type inwhich a mechanical escapement allows the warp beam to turn and let thewarps advance in direct accord with the tension imparted to the warps bythe pull of the take-up motion which draws forward the cloth as it iswoven.

' In the standard Roper let-off motion as applied to Draper looms, thepallet lever and the let-off ratchet Wheel are mounted by their hubsdirectly on the pinion shaft which carries at its inner end the let-offpinion that engages with the gear on the warp beam head to control theunwinding rotation of the Warp beam. In operation, the pallet lever isrocker back and forth continuously in time with the beat of the lay,being linked to an arm on the parallel foot on the lay rocker shaft. Thelet-01f ratchet wheel moves for varying distances, as determined by thevarying Warp tension, in the direction of rotation of the pinion shaftbut at twice the shafts speed of rotation, at nearly every beat of thelay. Even though these two parts are mounted free on the pinion shaftwhich so far as they are concerned merely serves as a stud or axle forsupporting them rotatably, and though the co-engaging bearing surfacesare presumably kept lubricated, they still urge on or hold back on thepinion shaft, with the result that the pinion shaft is allowed to turnunevenly. The resulting thick and thin places in the woven fabricoccasioned by variation in pick count (weft density) thus caused by thechanging rate of warp advance form serious and irreparable defects inthe quality of the finished fabric.

Also, this constant relative motion of the pallet lever and let-offratchet wheel against the pinion shaft increases the rate of wear ofthese parts unnecessarily.

Further, the entire weight of the let-off mechanism is borne by thepinion shaft with the major portion of it outside the loom frame,causing a tendency of the pinion shaft to tilt and bind within itssingle bearing provided in the let-off stand near the inward end of thepinion shaft.

Additionally, lint and fly have easy access to the hearing surfaces,being caught and held by the lubricant, increasing the friction drag onthe pinion shaft to affect the Warp feed adversely.

The present invention has as its leading aim the attainment of a morenearly constant rate of advance of the warps under the pull of thetake-up motion. Further objects of the invention are to eliminate theunnecessary wear of the pallet lever and let-01f ratchet wheel andpinion shaft created by letting the lever and wheel bear on the pinionshaft; and additionally to provide greater support for the pinion shaftand better shielding of the bearing surfaces of these parts from ingressof lint and fly to the bearing surfaces.

It is also an aim to provide these improvements in a form which can beapplied to existing let-off motions with a minimum of trouble andexpense, and with retention and use of all the original parts thereof.

Other objects of the invention, and the manner of their attainment, areas made plain hereinafter.

An illustrative embodiment of the invention is shown in the accompanyingdrawings, in which Fig. 1 is a rear elevation of the improved let-off,mainly in vertical section.

Fig. 2 shows the improved bearing and supporting element in sideelevation.

The relevant parts of a Roper type let-olf, modified in accordance withthe invention, are shown in Fig. 1, and comprise a let-01f pinion 1engaging with the beam gear 3 forming a part of the warp beam head (notshown), the pinion being fixed by screw 5 on the inward end of pinionshaft 7 extending through hub 9 formed as an integral part of let-offstand 11, which is bolted to the loom side. Hitherto, the interior ofhub 9 formed the bearing surface for pinion shaft 7, with the palletlever 13 and hub 15 of the let-off ratchet wheel 17 mounted rotatablydirectly on pinion shaft 7 by means of their respective hubs 19 and 21.

In accordance with the invention, however, the pinion shaft 7 is keptentirely out of contact with the pallet lever 13 and the ratchet wheelshub 15 and all other parts thereof, by providing a greatly extendedhearing or sleeve 23 which is press-fitted into the original bearingwithin hub 9 after boring out the passage through the latter to acceptit. The interior diameter of sleeve 23 throughout its length is madeappropriate to receive and serve as the bearing for pinion shaft 7. Thissleeve 23 preferably extends throughout the full length of hub 9, beyondwhich it has a cylindrical portion 25 of increased outside diameterabutting against hub 9, upon which portion 25 is mounted the hub 19 ofpallet lever 13, such hub being bored out and finished to rotate freelyon this enlarged portion 25. Next the hub 15 with its integral eccentric27 which drives the let-off internal gear pinion (not shown) workingWithin internal gear 29 as heretofore, is bored out and finished torotate freely on the reduced outside diameter of the outward end portion31 of sleeve 23, and mounted thereon. The ratchet wheel 17 is attachedin usual manner to the inward face of its hub 15 by cap screws 33. Asbefore, internal gear 29 and pinion shaft arm 35 with its pawls 37 aremounted directly on pinion shaft 7, the pinion shaft arm 35 beingsecured by set screw 39. All the usual additional parts of the standardRoper let-01f such as the pinion crosshead, friction clamp and dog,controlling lever, pinion shaft handle, and the rest, are present intheir usual 10- cations and utilized in the usual manner, though omittedfrom the drawing for clarity.

The novel sleeve 23 which thus provides internal and external bearingsurfaces for the stated parts is provided with oil holes 41 at locationsaimed to line up with the original oil holes 43 in hub 9. To provide forvariations in the location of the original oil holes 43, the sleeve 23is turned down to form shallow peripheral grooves 45 Wide enough toreceive oil introduced through the original passages 43 and conduct itto the oil holes 41 and thence to the interior bearing surface of sleeve23 and to pinion shaft 7.

The usual spacing collar 47 is applied to pinion shaft 7 to bear againstthe inward end of hub 9 for use in positioning pinion gear 1 properly inmesh with beam gear 3.

Although the present embodiment is designed to change over existinglet-off motions without replacement of the original parts, it will beunderstood that where new motions are to be built the inventionprinciple will be applied by omitting the sleeve 23 and extending thehub 9 with the formation of the bearing surfaces for the pellet lever 13and hub 21 of the ratchet wheel directly thereon in the same locationsas the bearing surfaces 25 and 31 of the sleeve 23.

While I have illustrated and described certain forms the scope of theinvention.

in which the invention may be embodied, I am aware that manymodifications may be made in the invention by any person skilled in theart, without departing from Therefore, I do not wish to be limited tothe particular formsshown, or to the details of construction thereof,but what I do claim is:

1. A warp let-off motion for looms having in combination apinion gear, apinion shaft, a let-off stand having a hub supporting the pinion shaft,a pallet lever, a ratchet wheel, and a sleeve fixed Within the let-ofi?stand hub and forming the bearing surface for the pinion shaft, palletlever, and ratchet wheel.

.2. A warp let-off motion for looms having in combination a let-ofistand having a hub, a pinion shaft extending through the hub, a sleevefixed within and extending from the hub :and surrounding the pinionshaft, a pallet lleverv .rotatably mounted on the sleeve, and a ratchetWheel also rotatably mounted on the sleeve.

3. vA warp let-ofi motion for looms having in combination a let-01fstand having a hub, a pinion shaft, a pinion gear thereon, a palletlever, a ratchet wheel, and ,a sleeve .fixed Within the hub forming thebearing surfaces for the pinion shaft, the pallet lever, and the ratchetwheel.

'4. A warp let-off motion for looms having in combination a leteofistand, a pinion shaft, a pallet lever, a ratchet wheel, and means infixed connection with the stand forming the bearing surfaces for thepinion shaft, the pallet lever, and the ratchet wheel.

5. A warp let-off motion for looms having in combination a let-offstand, a pinion shaft, a pallet lever, a ratchet wheel, and means infixed connection with the stand having internal bearing surfacesrotatably supporting the pinion shaft and external bearing surfacesrotatably supporting the pallet lever and the ratchet wheel.

6. A warp let-0E motion for looms having in combination a let-off standhaving a hub, a pinion shaft extending through such hub, a sleeve fixedin the hub having an internal bearing surface rotatably supporting thepinion shaft, and having a portion of increased diameter abutting thehub and forming an external bearing surface, a pallet lever rotatablymounted on the latter hearing surface, and a ratchet wheel, the sleevehaving a portion of reduced diameter located outwardly beyond theincreased diameter portion and forming an external bearing rotatablysupporting the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS647,815 Draper et al. Apr. 17, 1900 1,528,579 Stafford Mar. 3, 19252,609,006 Lord Sept. 2, 1952

